PRESS CONFERENCE: Uvalde authorities release new details on Texas school shooting

Texas Department of Public Safety Director Steven McCraw said Friday that nearly 20 officers were in a hallway outside of the classrooms for more than 45 minutes before agents used a master key to open a door and confront the gunman, Salvador Ramos. The on-site commander believed the gunman was barricaded in a classroom at the school during Tuesday's attack and that the children were not at risk.

How to talk to your kids about school shootings

The 18-year-old gunman who slaughtered 19 children and two teachers at a Texas elementary school barricaded himself inside a single classroom and "began shooting anyone that was in his way," authorities said Wednesday in detailing the latest mass killing to rock the U.S.